"HMS Pinafore" is a comic opera by Gilbert and Sullivan, first performed in 1878. The story is set aboard a British warship and revolves around the romantic entanglements of its crew and passengers. The main plot follows Josephine, the captain's daughter, who loves a common sailor named Ralph, but is pressured to marry Sir Joseph Porter, a wealthy and influential man. The opera is known for its catchy tunes, humorous dialogue, and satirical take on class distinctions and social norms. It features memorable songs like "I Am the Captain of the Pinafore" and has become a staple in the repertoire of operatic performances worldwide.